BORA Explorer back-end data-indexing service
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BORA Shell Crawler

This module collects index data to use BORA Shell Blockchain data in the BORA Explorer.


Required development environment

Java 1.8

BORA Explorer is a tool written in Java. Therefore, you need to install the JDK on the machine you want to build.


To construct a list for Block and Transaction, you need to build an index database. To understand MySQL and how to install, see MySQL Official Site. Please see here for scripts on related schemas.


A tool for building this project, requires gradle 4.x or later.

Understanding Spring Framework, Ethereum and Web3J

The BORA Explorer is a solution using the Java based Spring Boot Framework. In this regard, you need a basic knowledge of Java and Spring Boot. The BORA Explorer runs on an Ethereum-based node and its related API leverages Web3J. If you want to understand the code, you need to have prior knowledge of Ethereum and Web3J.


./gradlew clean build -x test

Run BORA Crawler Application

The BORA Crawler Application provides four options regards data collection. If no parameter is given, it starts with "Stream Mode" as a default.

Stream Mode

  • Indexing blocks and transactions from the current block number at the time of starting the application.
java \
  -jar ./build/libs/bora-explorer-point-crawler-0.0.1-SNAPSHOT.jar \

Catch-Up Mode

  • Indexing blocks and transactions since the last block number that was stored when the application was stopped.
java \
  -jar ./build/libs/bora-explorer-point-crawler-0.0.1-SNAPSHOT.jar \

Range-From Mode

  • Indexing blocks and transactions after the specified block number
java \
  -jar ./build/libs/bora-explorer-point-crawler-0.0.1-SNAPSHOT.jar \

Range Mode

  • Indexing blocks and transactions within the specified block number range
java \
  -jar ./build/libs/bora-explorer-point-crawler-0.0.1-SNAPSHOT.jar \
  --start=1096300 --end=1103000